The present invention relates to the field of catalysts and, more particularly, to a single step process for preparing an alkali-free acidic metallosilicate catalyst and to a process for preparing an alkali-free acidic multifunctional metallosilicate catalyst for use in various hydrocarbon reactions.
Protonic or acidic metallosilicate catalysts are frequently used for numerous hydrocarbon reactions, and are employed for example during the refining of hydrocarbons. Such reactions include, for example, alkylation, dealkylation, dehydrocyclodimerization, aromatization, transalkylation, isomerization, dehydrogenation, hydrogenation cracking, hydrocracking, reforming, cyclization, oligomerization, polymerization, dehydration and conversion of carbon monoxide/hydrogen mixtures to hydrocarbons.
Numerous methods have been developed for the preparation of catalysts and multifunctional catalysts (that is, a catalyst having more than one active metal serving more than one function).
Generally, such methods include the modification of a standard zeolitic catalyst support to protonic form through ion exchange procedures. At least one catalytically active metal is then impregnated or ion exchanged onto the acidic zeolite. This type of procedure, however, yields a poor spread of the active metal on the catalyst surface, thus yielding poor activity. Further, such ion exchange procedures are expensive. Finally, these procedures require the use of a support initially containing alkali and/or alkaline earth metals which further add to the cost involved.
It is thus the principal object of the present invention to provide a process for preparing an acidic catalyst which does not involve the use of ion exchange or impregnation procedures, and which does not require a starting support material containing alkali and/or alkaline earth metals and is, therefore, less expensive.
It is a further object of the present invention to provide a process for preparing a multifunctional catalyst which, as above, does not involve the use of ion exchange or impregnation procedures, and which does not require a starting support material containing alkali and/or alkaline earth metals and is, therefore, less expensive.
It is still another object of the present invention to provide such a process where the catalytically active metals have good surface dispersion and, therefore, good activity.
Other objects and advantages will appear hereinbelow.